A polycarbonate is a polymer excellent in transparency, heat resistance, and impact resistance, and hence has been widely used as an engineering plastic in an industrial field at present.
With regard to a method of producing the polycarbonate, a method involving causing an aromatic dihydroxy compound, such as bisphenol A, and phosgene to directly react with each other (interfacial polymerization method) has been known as a method of producing a high-quality polycarbonate. The following method has been adopted as an industrial production method for a polycarbonate based on the interfacial polymerization method (see Patent Documents 1 and 2). An alkali aqueous solution of a bisphenol and phosgene are caused to react with each other in the presence of an organic solvent to produce a polycarbonate oligomer having a reactive chloroformate group, and simultaneously or sequentially with the production of the polycarbonate oligomer, a condensation reaction (polymerization reaction) between the polycarbonate oligomer and the bisphenol is further advanced in the presence of a polymerization catalyst, such as a tertiary amine, and the alkali aqueous solution.
Among the polycarbonates, a polycarbonate-polyorganosiloxane copolymer (hereinafter sometimes referred to as “PC-POS copolymer”) obtained by copolymerization through the use of a polyorganosiloxane has been attracting attention because the copolymer has high impact resistance, high chemical resistance, and high flame retardancy. The copolymer has been expected to be widely utilized in various fields, such as the field of electrical and electronic equipment, and the field of an automobile. A polymerization catalyst, such as a tertiary amine, has been used at the time of the production of the polycarbonate for efficiently advancing a reaction (see Patent Document 3).